Onken was born the daughter of a priest in Oldenburg and started to imitate voices from an early age.
Her first successful radio programme was Die Pisa-Polizei with N-Joy and SWR 3, in which she confronted schoolchildren on the street and asked them difficult questions from various subject areas.
In 2005 she began to imitate the voice of politician (and later Federal Chancellor) Angela Merkel on The Gerd Show.
Her successful work with Elmar Brandt (who imitated Gerhard Schröder) culminated in the popular song "Im Wahlkampf vor mir liegt ein Zonenmädchen", which reached no.
In October 2005 The Gerd Show was replaced by a new comedy serial, Angela - Schicksalsjahre einer Kanzlerin - Eine Frau geht seinen Weg.